The invention relates generally to construction vehicles such as backhoes. More particularly, it relates to construction vehicles having auxiliary control valves for controlling the flow of hydraulic fluid to implements attached to the vehicle. Even more particularly, it relates to such vehicles with dual hand controls for controlling the auxiliary valve.
Construction and agricultural vehicles such as backhoes, front loaders, dozers and the like are provided with implements that are physically attached to the vehicles and are used in conjunction with other moveable elements of the vehicle.
For example, front loaders may equipped with post-hole diggers mounted on the front of the vehicle in place of the bucket that is normally used.
These implements are commonly dynamic, and include hydraulic motors that are powered by a hydraulic pump on the vehicle itself. Thus, the hydraulic pump can move the various jointed arms and levers of the vehicle using hydraulic power, and can also power the attachable implements using the same power source.
A further advantage to these assemblies is that the vehicle manufacturers typically put a valve control and switch or other manually operable member in the cab to control the flow of hydraulic fluid to the implement. This is understandably necessary, since not every implement requires the same amount of hydraulic fluid flow or pressure to operate.
Typical two-handled construction vehicles, such as those described above were modified to include a pressure regulator valve configured to regulate the flow of hydraulic fluid to the implement and a switch connected to an on-off valve to turn the flow either on or off to the implement.
For many implements, this was satisfactory. The operator could adjust the fluid flow rate by turning the flow control valve""s knob, then flip the on-off switch to start the implement moving. For those implements that needed a constant fluid flow rate, this was sufficient.
Unfortunately, other implements needed a variable flow rate as they were moved. In order to move the implements, it was necessary to hold and manipulate the two handles of the vehicle. The movement of the handles forward and backward causes the entire vehicle to go forward or backward. By pressing buttons on the handles, the various linkages in the vehicle""s boom or front loader linkage were caused to raise, lower, swing left, swing right, extend and retract.
It was impossible to vary the flow rate to the implement as the vehicle and its boom and loader linkages moved. In order to vary the flow rate, either by turning the auxiliary valve switch on and off, or by rotating the pressure regulator valve required the operator to remove his hands from the handles. Unfortunately, when he removed his hands from the handles, he could no longer either move the vehicle or the boom and loader linkages coupled to it.
More recently, a spring-loaded thumbwheel was provided on one of the hand controls to permit the aux flow rate to be changed without the operator""s hands being removed. Unfortunately, this required the operator to constantly maintain thumb pressure on the wheel to keep the desired flow rate. If for any reason the wheel was accidentally released, it would spring back to an xe2x80x9coffxe2x80x9d position. This arrangement was awkward, at best.
What is needed therefore, is an apparatus for controlling an attachable implement of a construction vehicle while permitting the operator to simultaneously move the vehicle, its boom or its loader. It is an object of this invention to provide such an apparatus.
In accordance with a first embodiment of the invention a work vehicle is described that is configured to be coupled to an implement operated by a flow of hydraulic fluid. the vehicle includes a chassis, an engine coupled to the chassis, a hydraulic pump rotationally coupled to the engine to generate a flow of pressurized hydraulic fluid, an auxiliary proportional control valve fluidly coupled to the pump to receive regulate and transmit the flow of pressurized hydraulic fluid and configured to be fluidly coupled to the implement and responsive to a valve-opening signal, an implement support arm pivotally coupled to the chassis and configured to be moved in at least two directions, a first hand control manipulable to move the arm in a first direction, the hand control including a first operator actuable switch, a second hand control configured to move the arm in a second direction different from the first direction, the second hand control including a second operator actuable control having a plurality of positions, and a digital controller coupled to both the first operator actuable switch and the second operator actuable control, wherein the controller is configured in a first mode of operation to generate the valve opening signal indicative of the position of the second operator-actuable control when the second control is in each of said plurality of positions, and further wherein the controller is configured in a second mode of operation to record a digital value indicative of the valve opening signal when the second operator actuable control is in each of the plurality of positions and when the operator actuates the first switch.
The first hand control may be disposed to be operated by one hand of the operator and the second hand control may be disposed to be operated by another hand of the operator. The first and second hand controls may be disposed to permit simultaneous operation by the operator. The support arm may be a backhoe assembly including a boom, a dipper and a bucket linkage. A first of the two directions may be the boom""s rotation about the pivotal axis.
In accordance with a second embodiment of the invention, a method of setting and retrieving a predetermined auxiliary hydraulic fluid flow rate for an implement actuated by a variable flow of hydraulic fluid that is attached to a hydraulically moveable arm extending from a work vehicle having an operator""s station and at least two hand controls, wherein one hand control is configured to drive a first actuator to move the member in a first direction and the second hand control is configured to drive a second actuator to move the member in a second direction different than the first direction, wherein the first hand control includes a first finger control configured to generate a signal when actuated by a finger, and the second hand control includes a second finger control that generates a varying signal based upon the degree of deflection of the second finger control is disclosed, the method including manipulating the first hand control to position the member in a first position, manipulating the second hand control to position the member in a second position different from the first position, engaging the first finger control, engaging the second finger control to generate a signal indicative of a desired auxiliary hydraulic fluid flow rate, substantially simultaneously with the first finger control, and automatically recording a digital value indicative of the desired auxiliary fluid flow rate based upon the simultaneous engagement of the first and second finger controls and a degree of deflection of the second finger control.
The method may include the steps of, releasing the first and second finger controls, re-engaging the first finger control after the step of releasing, and automatically generating the desired auxiliary hydraulic fluid flow rate in response to the step of re-engaging. The method may also include the steps of releasing the first and second finger controls, re-engaging the first finger control, re-engaging the second finger control to generate a second signal indicative of a second desired auxiliary hydraulic fluid flow rate, substantially simultaneously with the first finger control, and automatically recording a second value indicative of the second desired auxiliary fluid flow rate based upon the simultaneous engagement of the first and second finger controls. The method may also include the steps of turning the work vehicle off, turning the work vehicle on, and going to a predetermined auxiliary flow rate different from the desired auxiliary fluid flow rate.
In accordance with a third embodiment of the invention, a method of setting a predetermined auxiliary hydraulic fluid flow rate for an auxiliary hydraulic valve of a backhoe/excavator having two hand controls, and a seat, wherein one hand control is disposed to be grasped and operated by a left hand of the operator, and another hand control is disposed to be grasped and operated by a right hand of the operator, and further wherein the two hand controls are configured to perform the functions of swinging the backhoe boom, raising and lowering the backhoe boom, raising and lowering the dipper, and opening and closing a bucket linkage, and further wherein one of the hand controls has a momentary contact button, and another of the hand controls has a proportional input device disposed for use by the operator""s finger is disclosed, the method including the steps of engaging the button, engaging the proportional input device to generate a signal indicative of a desired auxiliary hydraulic fluid flow rate, substantially simultaneously with the button, automatically recording a value indicative of the desired auxiliary fluid flow rate based upon the simultaneous engagement of the button and proportional input device and a degree of deflection of the proportional input device, releasing the button and the proportional input device, re-engaging the button after the step of releasing, and automatically generating the desired auxiliary hydraulic flow rate after the step of re-engaging the button.